The present invention relates generally to non-deforming, deflectable, multi-lumen catheters and catheter procedures involving functional devices, such as laser delivery devices and drug delivery devices. More particularly, the invention relates to a kink-resistant and flexible catheter and method of use, particularly adapted for laser-assisted and/or drug-assisted percutaneous transluminal revascularization (PTMR). The distal tip of the catheter for guiding a laser delivery device, drug delivery device or other functional device extendable there through, is deflectable in at least one given plane. The invention may further an automatic catheter tip alignment system for maintaining constant relative positioning between the distal tip of the functional device and the distal tip of the catheter.
In the treatment of heart disease, one method of improving myocardial blood supply is called transmyocardial revascularization (TMR), the creation of channels in the myocardium of the heart. The procedure using needles in a form of surgical myocardial acupuncture has been used clinically since the 1960s. Deckelbaum. L. I., Cardiovascular Applications of Laser Technology, Lasers in Surgery and Medicine 15:315-341 (1994). The technique relieves ischemia by allowing blood to pass from the ventricle through the channels either directly into other vessels communicating with the channels or into myocardial sinusoids which connect to the myocardial microcirculation.
In the reptilian heart, perfusion occurs via communicating channels between the left ventricle and the coronary arteries. Frazier, O. H., Myocardial Revascularization with Laserxe2x80x94Preliminary Findings, Circulation, 1995; 92 [suppl II]:II-58-II-65. There is evidence of these communicating channels in the developing human embryo. In the human heart, myocardial microanatomy involves the presence of myocardial sinusoids. These sinusoidal communications vary in size and structure, but represent a network of direct arterial-luminal, arterial-arterial, arterial-venous, and venous-luminal connections. This vascular mesh forms an important source of myocardial blood supply in reptiles but its role in humans is poorly understood.
Numerous surgical TMR studies have been performed, including early studies using needles to perform myocardial acupuncture, or boring, to mechanically displace and/or remove tissue. Such studies have involved surgically exposing the heart and sequentially inserting needles to form a number of channels through the epicardium, myocardium, and endocardium to allow blood from the ventricle to perfuse the channels. The early studies using needles showed that the newly created channels were subject to acute thrombosis followed by organization and fibrosis of clots resulting in channel closure. Interest in TMR using needles waned with the knowledge that such channels did not remain open. However, interest in TMR procedures has recurred with the advent of medical lasers used to create TMR channels. Histological evidence of patent, endothelium-lined tracts within laser-created channels shows that the lumen of laser channels can become hemocompatible and resists occlusion. A thin zone of charring occurs on the periphery of the laser-created channels through the well-known thermal effects of optical radiation on cardiovascular tissue. Additionally, recent histological evidence shows probable new vessel formation adjacent collagen occluded transmyocardial channels, thereby suggesting benefits from TMR with or without the formation of channels which remain patent.
Surgical TMR procedures using laser energy have been described. U.S. Pat. No. 4,658,817 issued Apr. 21, 1987 to Hardy teaches a method and apparatus for surgical TMR using a CO2 laser connected to an articulated arm having a hand piece attached thereto. The hand piece emits laser energy from a single aperture and is moved around the surface of the heart to create the desired number of channels. U.S. Pat. No. 5,380,316 issued Jan. 10, 1995 to Aita et al. purports to teach the use of a flexible lasing apparatus which is inserted into the open chest cavity in a surgical procedure. A lens at the distal end of the flexible apparatus is used to focus laser energy, and the apparatus is moved about the surface of the heart to create the desired number of channels.
The foregoing discussion relates to surgical procedures, i.e. procedures which access the heart surgically, either via open heart surgery, or perhaps by minimally invasive surgical (MIS) methods if the design and size of the distal ends of the hand pieces are suitable for use in an MIS site. However, since TMR most often involves creating channels through the epicardium into the lower left chamber of the heart, it is desirable to create TMR channels in a percutaneous procedure, i.e. by extending a catheter apparatus through the vasculature into the ventricle and creating the channels through endocardial surfaces and into myocardium. Performing percutaneous TMR (PTMR) is desirable for a number of reasons. Percutaneous catheter procedures are typically less traumatic to the patient compared to surgical procedures. Adhesions between the pericardial sac and epicardium are eliminated. Percutaneous TMR with a catheter apparatus also offers an alternative solution to persons who are not candidates for surgical procedures.
Because TMR procedures generally involve creating a plurality of channels within the myocardium, performing the procedure percutaneously requires the ability to steer a catheter apparatus through the vasculature and maneuver the apparatus within the ventricle of the beating heart as rapidly as possible to create the channels without subjecting the heart to the undue stress of a lengthy procedure. Additionally, the ability to control and stabilize the catheter apparatus against the beating heart wall while creating channels with a laser is desirable for percutaneous procedures to ensure creation of channels as desired and to ensure that the laser is fired only within the myocardial tissue. TMR channels should be spaced and grouped appropriately to achieve the desired result without weakening or rupturing the heart muscle.
The early myocardial acupuncture procedures were not performed percutaneously. The Hardy CO2 laser delivery system described above is rigid, relatively large, and not adaptable for percutaneous use. The Aita ""316 patent does not suggest a method for percutaneous use of the laser delivery device described therein for surgical use.
U.S. Pat. No. 5,389,096 issued Feb. 14, 1995 to Aita et al. purports to teach one method of percutaneous TMR using an elongated flexible lasing apparatus with control lines and a focusing lens structure at the distal tip. The method uses pressure applied manually to attempt to stabilize the apparatus against the wall of the heart.
Several patents describe the use of catheters within the ventricle for percutaneous treatment of ventricular tachycardia. Such devices have a means to locate an arrhythmia site and ablate the site, at or just below the ventricle surface, using an electrode device or laser energy. U.S. Pat. No. 5,104,393 issued Apr. 14, 1992 to Isner teaches a catheter apparatus having a guiding Y-shaped sheath and guide catheter assembly for introducing an optical fiber into the ventricle. Positioning is described to enable a single burst of laser energy from a single aperture to ablate the site.
U.S. Pat. No. 5,190,050 issued Mar. 2, 1993 to Nitzsche teaches a steerable catheter with a handle and a tube, the distal tip of which may be selectively curved by controllably moving one of three flat, sandwiched shims relative to the others by manipulation of a handle portion.
U.S. Pat. No. 5,358,479 issued Oct. 25, 1994 to Wilson, incorporated herein in its entirety by reference, teaches another steerable catheter with a handle and an inner tube, the apparatus having a single elongated, substantially flat shim spring mounted within the tip of the catheter tube, the shim having at least one transverse or lateral twist which causes the tip of the catheter tube to assume a desired curvature.
Drug therapies with angiogenic growth factors may expedite and/or augment collateral artery development. xe2x80x9cBiologic Bypass with the Use of Adenovirus-Mediated Gene Transfer of the Complementary Deoxyribonucleic Acid for Vascular Endothelial Growth Factor 121 Improves Myocardial Perfusion and Function in the Ischemic Porcine Heart,xe2x80x9d by Mack et al., The J. of Thorac. and Cardiovascular Surgery, Vol. 115, No. 1, January 1998, p. 168-177, delivery of vascular endothelial growth factor (VEGF) can be delivered to targeted tissues, by means of a replication deficient adenovirus (Ad) vector, to induce collateral vessel development in ischemic myocardium for improvement of both myocardial perfusion and function. xe2x80x9cIntroduction of Neoangiogenesis in Ischemic Myocardium by Human Growth Factorsxe2x80x9d, by B. Schumacher et al, The J. of Thorac. and Cardiovascular Surgery, Vol. 115, No. 1, January 1998, p. 645-650, teaches the use of FGF-1, a growth factor produced using recombinant-DNA technology, for the treatment of coronary heart disease based upon development of new vessels and the formation of capillaries in areas of stenoses. xe2x80x9cConstitutive Expression of phVEGF after Intramuscular Gene Transfer Promotes Collateral Vessel Development in Patients with Critical limb Ischemia,xe2x80x9d Baumgartner et al., The J. of Thorac. and Cardiovascular Surgery, Vol. 115, No. 1, January 1998, p. 1114-1123, teaches intramuscular injection of naked plasmid DNA encoding an endothelial cell mitogen to cause formation of collateral blood vessels, improved distal flow in many limbs, including healing of ulcers and successful limb salvage.
U.S. Pat. No. 5,409,453 issued Apr. 25, 1995 to Lundquist et al. teaches a steerable medical probe with stylets. The device is designed for reducing the mass of a body part, such as for biopsy sampling or for removing prostatic tissue in the case of BPH. The torquable catheter has a control end and a probe end, the probe end having a stylet guide means with a flexible tip and a tip directing means extending from the control end to the flexible tip for changing the orientation of the central axis of the stylet guide means for directing a flexible stylet outward through the stylet port and through intervening tissue to targeted tissues.
U.S. Pat. No. 5,571,151 issued Nov. 5, 1996 to Gregory teaches a method for contemporaneous application of laser energy and localized pharmacologic therapy. The method comprises preparing a solution of a pharmacologic agent, inserting the catheter into the lumen, directing the catheter to the site, transmitting visible light to the site, flowing the light transmissive liquid through the catheter, viewing the site, transmitting laser energy through the liquid filled catheter to treat the site, and introducing a flow of the pharmacologic agent in solution into the catheter for contemporaneous discharge at the distal end into the lumen adjacent the site.
The use of superelastic and/or shape memory materials is widely known. Structure and Properties of Tixe2x80x94NI Alloys: Nitinol Devices and Components, Duerig et al., In Press, Titanium Handbook, ASM (1994) In general, binary compositions of Nickel (Ni) and Titanium (Ti), yield alloys with shape memory and superelastic properties. These alloys are commonly referred to as Nixe2x80x94Ti, nitinol, and other industry names. Their precise physical and other properties of interest are extremely sensitive to the precise Ni/Ti ratio used. Generally, alloys with 49.0 to 50.7 atomic % of Ti are commercially available, with superelastic alloys in the range of 49.0 to 49.4%, and shape memory alloys in the range of 49.7 to 50.7%. Due to a rapid decrease in the ductility of the material, binary alloys with less than 49.4 at % Ti are generally unstable. In general, these types of materials exhibit hysteresis, defined as a phenomenon exhibited by a system whose state depends on its previous history, and illustrated diagrammatically by the familiar upper and lower curves which meet at the ends and define an area under the curves. In the case of solid materials undergoing elastic hysteresis (as opposed to magnetic or electrical hysteresis), the curves are related to stress necessary to cause deformation or otherwise overcome existing stress in pre-stressed materials.
For the purposes of this disclosure, a distinction between superelastic materials and shape memory materials is made. Superelasticity refers to the highly exaggerated elasticity, or springback, observed in many Nixe2x80x94Ti alloys deformed at a specific temperature. The function of the material in many of such cases is to store mechanical energy. Though limited to a rather small temperature range, these alloys can deliver over 15 times the elastic motion of a spring steel, i.e., withstand a force up to 15 times greater without permanent deformation. Shape memory materials will refer to those materials which can be deformed, but which will freely recover their original shapes during heating, often utilizing electrical resistivity, or which will develop a large recovery stress when recovery is prevented. With regard to the present invention, it will be understood that the transition temperature of materials must, in general, be somewhat above body temperature.
U.S. Pat. No. 3,890,977 issued Jun. 24, 1975 to Wilson teaches kinetic memory electrodes, catheters and cannulae. These devices incorporate a material, such as a Nixe2x80x94Ti alloy, having heat-activated mechanical memory properties. The device is formed into an operative shape at a high temperature. Then, at a low temperature below its transitional temperature, it is reformed into a shape for ease of insertion into a guide catheter or the like or otherwise through a portion of a patients vasculature or other body lumen. When located in the organ or other desired region, those portions of the device constructed using such shape memory materials are heated to above their transitional temperatures, using electrically resistive elements, thereby returning the catheter to its original annealed anchoring or proper locating shape. An important drawback of the Wilson apparatus is that heat must be applied to the catheter tip. Complicated construction and electrical power distribution must be considered.
U.S. Pat. No. 5,114,402 issued May 19, 1992 to McCoy teaches a maneuverable distal apparatus with a temperature activated material of construction which, upon heating to a predetermined position, will assume a predetermined, memorized shape, and which upon cooling, will assume a different shape by action of a spring element urging the apparatus into the different shape.
U.S. Pat. No. 4,920,980 issued May 1, 1990 to Jackowski teaches a catheter with controllable tip. A wire member is loosely positioned inside a central bore of the catheter so that the distal tip of the catheter can be bent by pulling the wire member.
U.S. Pat. No. 5,279,596 issued Jan. 18, 1994 to Castaneda et al. teaches an intravascular catheter with kink resistant tip. The catheter has a construction utilizing proximal and distal components with varying degrees of stiffness or durometer. Additionally, the distal tip has a helical wire support member embedded therein, for providing kink resistance to the distal portion upon bending thereof.
U.S. Pat. No. 4,960,134 issued Oct. 2, 1990 and U.S. Pat. No. Re. 34,502 issued Jan. 11, 1994, both to Webster, Jr., teach a steerable catheter having a control handle with piston mounted therein and a puller wire extending from the housing of the handle, through the piston and through and coaxial with the catheter body. The puller wire extends into an offset lumen of the catheter tip wherein it is attached to the wall of the catheter tip, such that lengthwise movement of the piston relative to the housing results in deflection of the catheter tip.
U.S. Pat. No. 5,431,168 issued Jul. 11, 1995 to Webster, Jr. teaches a steerable open-lumen catheter. A first lumen which extends the entire length of the catheter is open at the distal end of the catheter. A second, off-set lumen contains a tightly wound coil spring with a puller wire slidably disposed within the coil spring. Manipulation of a handle portion results in deflection of the tip portion without deflection of the catheter portion.
A common mode of failure of steerable catheters of the prior art is that upon positioning and retraction of the pull wire or pull cable, the distal end of the catheter may deform and develop an xe2x80x9cSxe2x80x9d shape. The problem, as described, is often due to inadequately supported distal end of the catheter. This may prevent deflection of the distal tip in some cases. In other catheters, including drug delivery catheters, pinching of the outer jacket around an internally restricted drug delivery tube seals the saline lumen caused during bending of the assembly, which restricts advancing or retracting movement of the delivery tube within the saline lumen, and prevents flow of fluids either way through the saline lumen.
There is a need for deflectable percutaneous catheters, especially PTMR steerable catheters, which automatically maintain alignment of the distal end of the catheter with the distal end of a functional device therein during catheter deflection movement relative to an interior body surface, particularly a ventricular wall. There is also a need for catheters which are deflectable yet which resist kinking or distortion, thereby preventing advancement or retraction of the functional device therein or otherwise restricting proper use thereof. Additionally, it would be desirable to provide such a non-deformable, deflectable catheter with an optional automatic compensation mechanism for alignment of inner and outer portions of the system during deflection and use.
Thus, it is an advantage of the present invention to provide a non-deformable, deflectable catheter and method of use for percutaneous and other intra-vascular procedures, including but not limited to PTMR, or any stimulation procedure. The deflectable distal portion of the catheter resistant to kinking or other undesirable distortion during deflection and use thereof.
It is a further advantage of the present invention to provide a non-deforming catheter having a deflection and translation mechanism, a hollow outer jacket having a deflectable distal portion and an at least partially embedded pull wire lumen and coupled at a proximal end to the deflection and translation mechanism, a tip coupled to a distal end of the outer jacket, an inner tube with lumen in the hollow of the outer jacket, at least one functional device disposed in the lumen having a distal end extendable from the tip of the catheter and a pull wire contained in the pull wire lumen having a distal end coupled to the tip and a proximal end coupled to the deflection mechanism, the pull wire effecting non-deforming deflection of the deflectable distal portion of the outer jacket and functional device therein by movement of the deflection mechanism.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter wherein the deflectable portion bends up to about 270 degrees.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter with a coil embedded in the deflectable portion of the outer jacket.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter with an at least partially embedded shim in the deflectable portion of the outer jacket.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter with a coil embedded and an at least partially embedded shim in the deflectable portion of the outer jacket.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter with one or more notches in an outer surface of the outer jacket and aligned with the pull wire.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter with one or more notches in an outer surface of the outer jacket, aligned with the pull wire, and a coil embedded in the deflectable portion of the outer jacket.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter in which the pull wire lumen has a proximal end embedded in the inner tube and a distal end at least partially embedded in the deflectable distal portion of the outer jacket.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter with a relative movement compensation mechanism for maintaining alignment between the outer jacket and the functional device coupled to the deflection mechanism whereby movement of the deflection mechanism causes simultaneous movement of the relative movement compensation mechanism.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter wherein the outer jacket is comprised of one or more polymers having one or more flexibility.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter wherein the proximal end of the outer jacket further comprises a braided construction.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter wherein a distal portion of the apparatus comprises one or more radio opaque materials.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter wherein the functional device is an energy delivery device, such as a laser energy delivery device, optionally in combination with a drug delivery device, or a drug delivery tube with a piercing needle distal end.
It is a further advantage of the present invention to provide a non-deformable deflectable catheter wherein the translation mechanism is coupled to a drug delivery module, the functional device is a drug delivery tube with a piercing needle coupled to a distal end and further comprising a relative movement compensation mechanism for maintaining alignment between the outer jacket and the drug delivery tube coupled to the deflection mechanism whereby movement of the deflection mechanism causes simultaneous movement of the movement compensation mechanism.
It is a further advantage of the present invention to provide a non-deforming catheter apparatus for delivering drugs to the myocardium having a deflection mechanism, a drug delivery module coupled to the mechanism, a hollow outer jacket having a deflectable distal portion with an embedded coil and shim, each having a proximal end coupled to the deflection mechanism, a tip coupled to a distal end of the outer jacket, an inner tube with lumen in the hollow of the outer jacket, a pull wire lumen having a proximal end embedded in the inner tube and a distal end at least partially embedded in the deflectable distal portion of the outer jacket, a drug delivery tube disposed in the lumen and having a distal end with a piercing needle, a distal tip of the piercing needle extendable from the tip of the catheter, and a pull wire contained in the pull wire lumen and having a distal end coupled to the tip and a proximal end coupled to the deflection mechanism, whereby the pull wire effects non-deforming deflection of the deflectable distal portion of the outer jacket and drug delivery tube therein by movement of the deflection mechanism. It is yet a further advantage to have a relative movement compensation mechanism for maintaining alignment between the outer jacket and drug delivery tube when the deflectable distal portion is deflected, in combination with the deflection mechanism of the non-deforming drug delivery apparatus.
A further advantage of the present invention is to provide a non-deforming catheter apparatus for performing percutaneous transluminal myocardial revascularization comprising a deflection and relative movement compensation mechanism, a hollow outer jacket having a deflectable distal portion with an embedded coil and shim coupled at a proximal end to the deflection and relative movement compensation mechanism, a tip coupled to a distal end of the outer jacket, an inner tube with lumen in the hollow of the outer jacket, a laser energy delivery device disposed in the lumen having a distal end extendable from the tip of the catheter, a pull wire lumen having a proximal end embedded in the inner tube and a distal end at least partially embedded in the deflectable distal portion of the outer jacket; and a pull wire contained in the pull wire lumen having a distal end coupled to the tip and a proximal end coupled to the deflection and relative movement compensation mechanism, whereby the relative movement compensation mechanism maintains alignment between the outer jacket and laser energy delivery device when the pull wire effects non-deforming deflection of the deflectable distal portion of the outer jacket and laser energy delivery device therein by movement of the deflection mechanism.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings.